Bicinchoninic Acid Assay (BCA) is a protein quantification method based on the biuret reaction. Under alkaline conditions, protein peptide bonds reduce Cu2+ ions from copper sulfate to Cu+, subsequently forming a purple-colored complex by chelating Cu+ with BCA, which strongly absorbs at a wavelength of 562 nm. The color intensity of the chelate is correlated with protein concentration, while the reduction of Cu2+ to Cu+ is directly proportional to the amount of protein present in the solution. Thus, protein concentration can be determined by measuring the absorbance. This kit is specifically designed to quantify low-concentration protein samples, measuring total protein concentrations in the range of 0.5-20 碌g/mL. The kit features ease of operation, excellent stability, high sensitivity, and wide compatibility. It exhibits good compatibility with many ionic and non-ionic detergents.